Not all ECUs can be reprogrammed. Try finding anyone who can custom program the ECU in a Contour. It may be similar to a ZX2, but it isn't the same, and the motor won't even start if you try to use a ZX2 ECU on it. I'm sure there are other examples out there.

Can you readjust a carburettor for better tuning? YES. Without allowing ECU mods, can you tune a car without a carb? NO. Is that fair?